Diapers having a zoned non-attachable back sheet and methods of manufacturing same

ABSTRACT

According to one embodiment, an absorbent article to be worn about a wearer has a front portion and a back portion. The absorbent article includes an outer layer, an inner layer that is substantially co-extensive with the outer layer, an absorbent layer and one or more fasteners, which are located on the back portion of the absorbent article. The absorbent layer is interposed between the outer layer and the inner layer to form the absorbent article. The outer layer has a central portion between two side portions. The central portion of the outer layer is treated with a chemical to substantially inhibit attachment of the one or more fasteners to the central portion of the outer layer. The one or more fasteners secure the back portion to the outer layer of the front portion. Specifically, the one or more fasteners are configured to secure the back portion to a region of the outer layer which is not treated with the chemical.

FIELD OF THE INVENTION

The present invention relates generally to an absorbent article and, inparticular, a disposable diaper or incontinence brief that requires awearer or caregiver to select an appropriately-sized disposable diaperor incontinence brief for the wearer.

BACKGROUND

Adult incontinence briefs, disposable diapers, and other absorbentarticles are designed to absorb and contain liquid and other dischargesfrom the human body to prevent body and clothing soiling. Often, anill-fitting absorbent article is chosen for a wearer. One reason for theill-fit is due to the fact that the size determination of absorbentarticles is often based on a single criteria such as a wearer's weight,hip circumference, or waist circumference. Thus, other relevant factorssuch as age, height, thigh circumference, and rise are not taken intoaccount. Alternatively, a wearer or caregiver may purposely choose alarger-sized absorbent article under the mistaken belief that it willhave a greater absorbency and, hence, be more beneficial. In reality,however, an oversized absorbent article may slip, slide, sag, or droop,any of which may cause discomfort and/or leakage.

Unlike determining that an absorbent article is too small for a wearer,determining that an absorbent article is too large for a wearer can bedifficult and problematic. It is evident when an absorbent article istoo small for a wearer because the fastening components, typicallylocated on a back portion of the absorbent article, will notsufficiently reach the front portion of the absorbent article, thusmaking it impossible to secure the absorbent article to the wearer. Incontrast, when an absorbent article is too large for a wearer, the backportion may be wrapped around the wearer's waist such that the fasteningcomponents may be attached anywhere on the back sheet (i.e., theexterior of the absorbent article) of the absorbent article. Becausewearers of absorbent articles are often very young children or elderlypersons, the wearers may be unable to walk or move freely and thereforemay be unlikely to notice the absorbent article sagging or drooping.Moreover, the wearer may not be able to effectively communicate to hisor her caregiver that the absorbent article is too large. In othercases, the ill-fit may be relatively subtle, leading the wearer tomistakenly believe that a proper fitting absorbent article was chosen.

Downsizing an absorbent article has several benefits to the wearer.First, downsizing to an absorbent article that provides a better fit islikely to reduce leakage as the smaller absorbent article will be lesslikely to slip, slide, sag, or droop. Moreover, downsizing an absorbentarticle may be more cost effective. Larger-sized absorbent articles aretypically more expensive than smaller-sized absorbent articles ofcomparable absorbency. This is due to the fact that larger absorbentarticles require the use of more absorbent materials and are, thus, morecostly to manufacture. Often, a case of larger-sized absorbent articleswill cost the same as smaller-sized absorbent articles but will containconsiderably fewer absorbent articles.

Therefore, there exists a need for an absorbent article that requires orforces a wearer or caregiver to select a properly-fitting absorbentarticle.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other advantages of the invention will become apparentupon reading the following detailed description and upon reference tothe drawings.

FIG. 1 illustrates a top view of an outer layer of a disposable diaperaccording to one embodiment.

FIG. 2 illustrates a cross-section view generally taken through sectionline 2-2 of the diaper of FIG. 1.

FIGS. 3A and 3B illustrate a right and a left side view, respectively,of the diaper of FIG. 1.

FIG. 4 illustrates an operational flow diagram for manufacturing adisposable diaper according to one embodiment.

FIG. 5A illustrates a side view of a kiss roll process according to oneembodiment.

FIG. 5B illustrates a front view of a kiss roll process according to oneembodiment.

FIG. 6 illustrates a top view of a spraying process according to oneembodiment.

While the invention is susceptible to various modifications andalternative forms, specific embodiments have been shown by way ofexample in the drawings and will be described in detail herein. Itshould be understood, however, that the invention is not intended to belimited to the particular forms disclosed. Rather, the invention is tocover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the invention.

DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

Absorbent articles described herein generally include an outer layerthat is zone-treated with a chemical to require a wearer or caregiver toselect a properly-fitting absorbent article for the wearer. Although theremainder of the description of the illustrative embodiments will bespecifically directed toward a disposable diaper, it is to be understoodthat the embodiments may also be implemented for other absorbentarticles such as, for example, adult incontinence briefs and that theproperties and uses described below apply to these other absorbentarticles as well.

Referring to FIG. 1, a top view of a disposable diaper 10 according toone embodiment is illustrated. The diaper 10 is of a substantiallyrectangular configuration to fit comfortably around a wearer; however,it is contemplated that any other suitable configuration can beemployed. The diaper includes a middle portion 18 located between a backportion 14 and a front portion 16. The middle portion 18 is contoured inan “hourglass” configuration to fit comfortably around a wearer's thighswhen the diaper 10 is secured to the wearer.

The diaper 10 generally consists of several layers, as shown in FIG. 2.FIG. 2 is a cross-sectional view of the diaper 10 generally alongsection line 2-2 shown in FIG. 1. The diaper 10 includes an inner layer20, which faces a wearer when the diaper 10 is secured to the wearer.The inner layer 20 can be a non-woven, permeable fabric made from anysuitable material such as, for example, polypropylene, polyethylene,polyester, materials having hydrophobic properties, combinations thereofand/or the like. Additionally, the inner layer 20 can be treated with ahydrophilic finish to improve pass through of liquids to diaper layersbeneath the inner layer 20. Non-limiting examples of suitablehydrophilic finishes include anionic surfactants, catonic surfactants,nonionic surfactants, wetting agents (e.g., silicon based surfactants,glycol based surfactants), combinations thereof and/or the like. As willbe discussed in greater detail below, the inner layer 20 is typicallyformed from a plastic resin of any of the above-referenced materials.

The diaper 10 also includes a non-woven, liquid-impervious outer layer12, which faces away from the wearer when the diaper 10 is secured tothe wearer. The outer layer 12 may be made of any material suitable tominimize or prevent fluids and other discharge from escaping the diaper.Non-limiting examples of suitable materials for the outer layer 12include polyethylene and/or breathable poly. According to someembodiments, the outer layer 12 can be a thin film such as, for example,polyethylene film. As will be discussed in greater detail below, theouter layer 12 is formed by any process that is suitable to form anon-woven fabric of fibrous loops. This outer layer 12 is substantiallyco-extensive with the inner layer 20.

An absorbent layer 22 is positioned between the inner layer 20 and theouter layer 12. The absorbent layer 14 may be composed of any materialssuitable for absorbing bodily fluids and discharge including, but notlimited to, a fibrous material (e.g., fluffed wood pulp), a superabsorbent polymer (SAP), or the combination of SAP and a fibrousmaterial. The SAP can be natural or synthetic and may be biodegradable.Non-limiting examples of SAP include polymers based on acrylate(s) suchas sodium acrylate, potassium acrylate, and/or an alkyl acrylate(s)(e.g., methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate,and hexyl acrylate). The absorbency of the diaper 10 may vary dependingupon whether it is intended for use by infants, children and/or adults.

Referring back to FIG. 1, a top view of the outer layer 12 of the diaper10 is shown. The diaper 10 includes features designed for securing thediaper 10 to a wearer. For example, the diaper 10 has fasteningcomponents 24 positioned on opposite sides 26 a, 26 b of the diaper 10.Each of the fastening components 24 has a fixed end 28 and a free end30. The fixed end 28 can be secured to the inner layer 20, the outerlayer 12, or both. The free end 30 extends outwards beyond the fixed end28 in a transverse direction. The free end 30 includes a fastener member32 comprising a plurality of hooks that are suitable to engage andattach to the fibrous loops inherent in the outer layer 12. Theplurality of hooks are configured to provide adequate strength ofattachment such that the fastener member(s) 32 remains attached to theouter layer 12 under ordinary conditions of diaper use. The fastenermember(s) 32 can be made from suitable materials such as, for example,nylon, polyester, polyamide, combinations thereof, and/or the like. Inthe embodiment shown in FIG. 1, the fixed ends 28 are secured to theback portion 14, thus allowing the free ends 30 to contact and attach tothe outer layer 12 of the front portion 16 when the diaper is folded andpositioned on a wearer, as shown in FIGS. 3A and 3B.

It is contemplated that in alternative embodiments the fasteningcomponents 24 may have a fixed end 28 secured to the front portion 16and a free end 30 for attachment to the back portion 14; however, it maybe more convenient to fix the fastening components 24 to the backportion 14 as described above with respect to FIGS. 1, 3A and 3B. It isfurther contemplated that according to some embodiments, the fasteningcomponents 24 may be integrally formed with the inner layer 20, theouter layer 12, or both. According to other embodiments, the fasteningcomponents 24 may not include a fixed end 28. Rather, the fasteningcomponents 24 may have two free ends 30, each free end 30 including afastener member 32, with one free end 30 attached to the front portion16 and the other free end 30 attached to the back portion 14. While theembodiment described with respect to FIG. 1 includes two fasteningcomponents, it is contemplated that any number of fastener componentscan be provided.

Referring again to FIG. 1, the outer layer 12 has a central portion 34located between two side portions 36. The central portion 34 of theouter layer 12 is treated with a chemical coating. The chemical coatinggenerally alters some of the functional properties of the fibers in thecentral portion 34. In particular, the chemical coating substantiallyinhibits or prevents the hooks of the fastener members 32 from attachingto the fibrous loops of the central portion 34. Non-limiting examples ofsuitable chemical coatings include urethanes, acrylic, vinyls, epoxies,silicone binders, fluorocarbon polymers (e.g., polytetrafluoroethylene(PTFE)), combinations thereof and/or the like.

The chemically-treated central portion 34 forces a wearer or a caregiversecuring the diaper 10 to the wearer to downsize the diaper 10 when thediaper 10 is too large for the wearer. In order to secure the diaper 10to the wearer, the side edges 26 a, 26 b of the back portion 14 aregrasped and pulled in opposite directions, laterally and outwardly,stretching the back portion 14 so that it lies flat and snug against thewearer. As used herein, the word “snug” refers to a fitting of thediaper that is comfortable for the wearer, yet tight enough to hold thediaper secured to the wearer under ordinary diaper use conditions. Eachof the sides 26 a, 26 b should be pulled with generally the same amountof force so that the diaper 10 remains positioned generally evenly andsymmetrically on the wearer. The side edges of the front portion 38 a,38 b are also pulled so that the front portion 16 lies flat and snugagainst the wearer' s abdomen. The free ends 30 of the fasteningcomponents 24 are pressed to a section of the front portion 16 of thediaper 10 located as far around the wearer's waist as the free ends 30will comfortably reach so that the side edges 26 a, 26 b of the backportion 14 overlap the side edges 38 a, 38 b of the front portion 16.

If, after the free ends 30 are pressed to the outer layer 12 of thefront portion 16, the fastener members 32 remain attached to the outerlayer 12, the correct size diaper 10 has been chosen. FIGS. 3A and 3Bshow the diaper 10 of FIG. 1 being properly fit to the wearer. On theother hand, if the fastener members 32 do not attach to the outer layer12, the diaper 10 is too large for the wearer. Because the hooks of thefastener members 32 cannot attach to the loops of the chemically-treatedcentral portion 34 of the outer layer 12, the wearer or caregiver isforced to downsize to a properly-fitting diaper.

In one embodiment, a diaper 10 designed to fit a waist size of about 59inches (about 150 cm) to about 66 inches (about 168 cm) includes acentral portion 34 having a width (i.e., parallel to the wearer's waist)of about 7 inches (about 18 cm) and a length (i.e., perpendicular to thewearer's waist) of about 37 inches (about 94 cm). In another embodiment,a diaper 10 designed to fit a waist size of about 32 inches (about 81cm) to about 42 inches (about 107 cm) includes a central portion 34having a width of about 7 inches (about 18 cm) and a length of about 31inches (about 79 cm). These dimensions are intended as non-limitingexamples and it is contemplated that any other suitably-sized centralportion 34 may be utilized.

It is contemplated that according to alternative embodiments, thechemical coating can also include a colorant. As a result, thechemically-treated central portion 34 would also provide a visualindicator of whether the diaper is properly-sized in addition tophysically preventing a wearer or a caregiver from choosing anill-fitting diaper.

It is also contemplated that the central portion 34 of the outer layer12 can be shaped and sized according to configurations that aredifferent than that illustrated in FIG. 1. For example, the centralportion 34 may be applied only to the front portion 16 of the outerlayer 12. As another example, the central portion 34 may comprise twochemically-treated portions with an untreated portion therebetween.

Referring to FIG. 4, a diagram illustrates the operational flow formanufacturing an absorbent article such as a disposable diaper accordingto some embodiments. In its most basic form, the method of manufacturinga diaper 100 includes forming an absorbent layer 22 (block 102), formingan inner layer 20 (block 104), forming an outer layer 12 (block 106),treating a central portion 34 of the outer layer 12 with a chemicalcoating (block 108), interposing the absorbent layer 22 between theouter layer 12 and the inner layer 20 (block 110), joining the innerlayer 20, absorbent layer 22 and outer layers 12 (block 112), andcoupling fastening components 24 a, 24 b to the diaper 10 (block 114).Each of these steps will now be described in more detail.

At block 102, the absorbent layer 22 can be formed from the superabsorbent polymers and fibrous material(s) by any suitable process. Forexample, the absorbent layer 14 can be formed on a conveyor belt passingunder a series of pressurized nozzles. Depending upon the desireddensities and distributions of SAP and fibrous material within theabsorbent layer 14, a particular pressurized nozzle in the series ofpressurized nozzles may spray SAP particles, fibrous material, or amixture of SAP and fibrous material onto the conveyor surface. Thebottom of the conveyor belt surface is perforated and a vacuum isapplied from below so that the fibers are pulled down to form a longflat absorbent pad as the materials are sprayed onto the conveyor belt.An absorbent pad of uniform thickness can be achieved by a levelingroller used to remove a portion of the SAP and/or fibrous material(s).The result of this process is a long uniform pad of absorbent material(“an absorbent pad”) that is subsequently cut to form the absorbentlayer 22.

At blocks 104 and 106, the inner layer 20 and the outer layer 12 areformed by any dry laid or wet laid process. For example, the inner layer20 and the outer layer 12 may be formed by a melt blown process,spunbond process, spunlace process, spunlaid process or the like.According to a melt blown process, a plastic resin (e.g., polypropylene,polyester, polylactic acid resin, or polyethylene) is melted andextruded though small holes by air pressure. The fibers condense onto asheet as the air-blown stream of fibers cools. Heated rollers are thenused to flatten the fibers and bond them together. The result is a “web”of nonwoven fabric, which can be rolled to form a bolt of fabric. Thus,an inner web is the web of fabric comprising the inner layer 20 of adiaper 10 and the outer web is the web of fabric comprising the outerlayer 12 of the diaper 10.

At block 108, the web of fabric comprising the outer layer 12 of adiaper (“the outer web”) is treated with a chemical coating by anysuitable process such as, for example, a kiss roll coating process, aslot die coating process, or a spraying process. A kiss roll process 200is illustrated in FIGS. 5A and 5B. A coating roll 214 is disposed belowthe outer web 212. A trough 216 containing the chemical coating 218 isdisposed beneath the coating roll 214 such that a lower portion of thecoating roll 214 is immersed in the chemical coating 218. As the outerweb 212 is transported past the coating roll 214, the coating roll 214rotates to carry a metered film of chemical coating 218 into contactwith the outer web 212.

The outer web 212 will eventually be cut into smaller pieces to producean outer layer 12 for a plurality of diapers. To ensure that only thecentral portion 34 of an outer layer 12 produced from the outer web 212is treated with the chemical coating 218, the coating roll 214 ispartitioned into one or more coating portions 220 and non-coatingportions 222. Accordingly, the coating portions 220 are disposed beneathportions of the outer web 212 to which the chemical coating 218 isapplied and non-coating portions 222 are disposed beneath portions ofthe outer web 212 to which the chemical coating is not applied.

As shown in FIG. 5B, the coating roll 214 includes a coating portion 220located between two non-coating portions 222. The coating portion 220 ofthe coating roll 214 has a width corresponding to the width of a centralportion 34 of an outer layer 12 that will be produced from the outer web212. The non-coating portions 222 are designed to prevent or minimizethe amount of chemical coating 218 applied to the outer web 212. Forexample, the non-coating portions 222 can be wrapped with a fabric thateither has inherent hydrophobic properties or is treated with ahydrophobic chemical. Non-limiting examples of hydrophobic fabricsinclude polypropylene fabric, polyethylene fabric and polyester fabric.The hydrophobic fabric may be a non-woven fabric. Non-limiting examplesof hydrophobic chemicals for use with the fabric on the non-coatingportions 222 include stearic acid, melamine based chemicals,fluorocarbon chemicals, and silicon based chemicals. When wrapped with ahydrophobic fabric, a minimal amount of chemical coating 218 is pickedup by the non-coating portions 222. Much of the chemical coating 218that is picked up quickly beads off of the non-coating portions 222. Asa result, only a negligible amount, if any, of the chemical coating 218is brought into contact with the outer web 212 by the coating roll 214.

It is contemplated that two or more coating rolls can be positioned sideby side across the width of the outer web. Additionally, a coating rollmay have one or more coating portions, any number of non-coatingportions, or no non-coating portions at all. These variations may beadvantageous when multiple outer layers are to be produced across thewidth of the outer web. It is further contemplated that multiple coatingrolls may be employed at intervals along the transport path of the outerweb to apply multiple coatings of the chemical coating to the outer web.

According to an alternative embodiment, the chemical coating 318 can bedeposited on the appropriate portion(s) of the outer web 312 by aspraying process 300 as shown in FIG. 6. In the illustrated embodiment,two outer layers will be produced across the width of the outer web 312;however, it is contemplated that any number of outer layers can beproduced across a width of the outer web 312 depending upon the size ofthe diaper 10 and the width of the outer web 312. Each of the outerlayers will have a corresponding central portion 334. Two spray nozzles314 are coupled to a reservoir (not shown) containing the chemicalcoating 318. As the outer web 312 passes beneath the spray nozzles 314,the chemical coating 318 is sprayed onto the outer web 312. The twospray nozzles 314 are disposed above the outer web 312 so that thechemical coating 318 is only sprayed onto the portions of the outer web312 that correspond to a central portion 334 of the outer layers thatwill be produced from the outer web 312. It is contemplated thataccording to some embodiments the chemical coating 318 can be sprayedfrom the sprayers 314 in foam form. Specifically, chemical coating 318can be printed (i.e., sprayed through small spray nozzles in closeproximity to a target surface) onto the outer web 312 to precisely applythe chemical coating 318 to the outer web 312. Optionally, the outer webcan be placed in an oven to dry the chemical coating applied by the kissroll process, the spraying process, or any other suitable applicationprocess.

At this point in the manufacturing process, an inner web, an absorbentpad, and an outer web have been formed. At block 110, the absorbent padis interposed between the inner web and the outer web by, for example,feeding the absorbent pad onto a conveyor with the outer web and thenfeeding the inner web into place above the absorbent pad. At block 112,the interposed layers are joined by a suitable means such as, forexample, gluing, heating, calendaring, ultrasonic welding or the like.If not integrally formed, at block 114, the fixed ends of the fasteningcomponents are secured to the inner layer 20, the outer layer 12 or bothby, for example, gluing, heating, calendaring, ultrasonic welding or thelike. Optionally, elastic bands may be added as well to facilitate asnug fit and prevent leakage. The assembled layers are then cut intoindividual diapers. The diapers are cut to a shape and size desired forthe anticipated end users (e.g., infants, children, and/or adults).

It will be appreciated by those skilled in the art that many of thesteps for manufacturing the diaper or other absorbent article can beperformed in a different order than that described above. For example,the absorbent layer 22, the inner layer 20, and the outer layer 12 canbe formed in any order. Additionally, it is contemplated that the outerlayer 12 can be chemically treated after interposing the absorbent layer22 between the inner layer 20 and the outer layer 12 or after joiningthe inner layer 20, the absorbent layer 22, and the outer layer 12.

While the present invention has been described with reference to one ormore particular embodiments, those skilled in the art will recognizethat many changes may be made thereto without departing from the spiritand scope of the present invention. Each of these embodiments andobvious variations thereof is contemplated as falling within the spiritand scope of the claimed invention, which is set forth in the followingclaims.

1-19. (canceled)
 20. An absorbent article to be worn by a user, theabsorbent article comprising: an outer layer having at least oneattachment portion and at least one non-attachment portion; an innerlayer substantially co-extensive with the outer layer; an absorbentlayer interposed between the outer layer and the inner layer; at leastone fastener adapted for securing the absorbent article to the user; andwherein the non-attachment portion is treated with a chemical thatinhibits attachment of the at least one fastener to the non-attachmentportion.
 21. The absorbent article of claim 20, wherein the chemicalcomprises at least one of acrylics, vinyls, urethanes, epoxies,fluorocarbon polymers and silicone binders.
 22. The absorbent article ofclaim 20, wherein the chemical includes a colorant for visuallyindicating if the absorbent article is properly-fitted.
 23. Theabsorbent article of claim 20, wherein the non-attachment portion islocated on a central portion of the outer layer.
 24. The absorbentarticle of claim 20, wherein the non-attachment portion comprises twochemically-treated portions with an untreated portion therebetween. 25.The absorbent article of claim 20, wherein the outer layer is anon-woven, liquid-impervious material.
 26. The absorbent article ofclaim 20, wherein the inner layer is a non-woven, permeable material.27. The absorbent article of claim 26, wherein the inner layer istreated with a hydrophilic finish to improve pass-through of liquids.28. The absorbent article of claim 20, wherein the absorbent layer ispositioned between the outer layer and the inner layer and is comprisedof materials suitable for absorbing bodily fluids and discharge.